Question

How does ordinary light differ from plane polarized light?

Answer 1

Difference between plane polarized light and ordinary light:

Terms	Plane Polarized Light	Ordinary Light
Definition	A type of EMR with vibrations that take place only in one plane is called plane polarized light	Ordinary light, also known as unpolarized light, is an EMR in which all of the light waves oscillate in different directions
Direction of oscillation	Occurs in one direction only	Occurs in random directions
Phase difference	The constant phase difference between $x$ and $y$ components of electric field	Phase difference changes unpredictably
Light source	A polarization filter's output of light waves	Sunlight and other sources of natural light

Hence, while all of the oscillations in normal light are perpendicular to the route of propagation, all of the oscillations in-plane polarized light are in the same plane.